During the London Olympics, a prominent group of U.S. track and field athletes headed up the #WeDemandChange movement on Twitter protesting Rule 40, the International Olympic Committee provision which prohibits athletes from promoting non-official sponsors during a period around the Games.

Friday, the group behind the movement, the Track and Field Athletes Association, went global and announced that it was being joined by international athletes, including Usain Bolt and Yohan Blake.

"We recognize that the challenges faced by track and field athletes are not limited to Team USA," said TFAA President Khadevis Robinson, a U.S. middle-distance runner. "In order to grow our sport, we must establish a unified voice across the international community of athletes."

U.S. Olympic Committee CEO Scott Blackmun said Friday that he can see both sides of the issue. He spoke to news reporters during a conference call following a USOC board meeting.

"I understand the desire and need on part of the athletes to try to create some real estate that they can sell during the 16 days that they're really in the peak of their careers," Blackmun said. "I am sympathetic to the need and desire to do that. I don't know anything about the specific proposal so I can't comment on it, but the truth is we would like to find ways for the athletes to benefit from their success at the Olympic Games. We also understand the critical need to protect the integrity of the games and exclusivity of the sponsors. They provide substantial funds for our Olympic athletes. So it's not an easy question at all but we look forward to learning more about it."

Track athletes hope to push for change in the same way other pro sports unions do. One of the most prominent athletes involved is Sanya Richards-Ross, who won the gold in the 400 in London and whose husband, Aaron Ross, is a cornerback for the Jacksonville Jaguars.

"I've seen my husband, who has been in the NFL for six years, and I've seen what a strong players' union does, not only for the benefit of the players but the benefit of the sport," Richards-Ross told ESPN.com. "And thisis global. There are unions in every industry because they need to have that voice, not just for financial reasons but for consideration of other things.

"This should have happened 20 years ago. It's well overdue. It only makes sense to unite."